As the Cedar River is expected to reach a crest of 18.6 feet Monday into Tuesday, the National Weather Service will be updating the forecast and current readings every hour. You can monitor these levels with this map.

The substance was ready to break out this summer after the U.S. Food and Drug Administration, following years of back-and-forth, declined to challenge findings voluntarily presented by the company that the cooked product is “generally recognized as safe,” or GRAS.

Such a “no questions” letter means the FDA found the information provided to be sufficient.

Heme is “responsible for the flavor of blood,” Impossible Foods CEO Patrick Brown said in an interview earlier this year. “It catalyzes reactions in your mouth that generate these very potent odor molecules that smell bloody and metallic.”

It’s how it looks that’s at issue, though. An FDA spokesman said heme, which is red in hue, needs to be formally approved as a color additive before individual consumers can purchase the uncooked product.

Impossible Foods says heme isn’t a color additive as currently used in cooked Impossible Burgers sold in restaurants. However, other future uses might qualify as a color additive, company spokeswoman Rachel Konrad said in an email.

The company submitted the FDA petition to retain “maximum flexibility as our products and business continue to evolve.” Konrad declined to say whether uncooked heme-containing products to be sold in supermarkets were one of those contemplated future uses.

“Impossible Foods is in full compliance with all federal food-safety regulations and has been since 2014, well before we launched a product at restaurants in 2016,” she said.

The color additive FDA filing won’t affect the continued sale of cooked Impossible Burgers in restaurants, and approval by the regulator of the color-additive petition could come in time for the company to roll out the raw product next year, as planned.

The demand for it definitely exists. Once just the province of animal welfare advocates and the health conscious, the meat-alternative market has turned white-hot, given the massive role industrial meat production plays in global warming.